<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>在线计算器</title>
<style>
    body {
        font-family: Arial, sans-serif;
        text-align: center;
    }
    h1 {
        color: #333;
        margin-top: 50px;
    }
    form {
        margin-top: 20px;
    }
    input[type="text"] {
        padding: 5px;
        margin: 5px;
    }
    select {
        padding: 5px;
        margin: 5px;
    }
    input[type="submit"] {
        padding: 10px 20px;
        background-color: #007bff;
        color: #fff;
        border: none;
        cursor: pointer;
    }
</style>
</head>
<body>

<h1>在线计算器</h1>
<form action="/test_cgi" method="GET">
    <label for="num1">num1:</label>
    <input type="text" id="num1" name="num1" value="0"><br>
    
    <label for="num2">num2:</label>
    <input type="text" id="num2" name="num2" value="0"><br>
    
    <label for="op">操作符:</label>
    <select id="op" name="op">
        <option value="add">+</option>
        <option value="sub">-</option>
        <option value="mul">*</option>
        <option value="div">/</option>
    </select><br><br>
    
    <input type="submit" value="提交">
</form>

</body>
</html>


